As a new feature to help states pass the most effective drunk driving laws, this year’s five categories each have two subcategories, allowing for half-star ratings for states that need to improve their existing laws. For example, all states that conduct sobriety checkpoints receive a half-star, but those that conduct them at least once a month receive a full star.

The report comes just as the country begins six weeks of holiday celebrations that mark a deadly period of drunk driving crashes. In 2015, 973 people were killed in drunk driving crashes between Thanksgiving and New Year’s Day — nearly 10 percent of all drunk driving crashes for the year.

On the day before and day of Thanksgiving and Christmas, 33 to 39 percent of all traffic fatalities were caused by drunk driving.